Ear manifestations of connective tissue diseases: A dermatologic, histopathologic, and clinicopathologic review

Connective tissue diseases comprise a spectrum of autoimmune disorders characterized by chronic inflammation and immune-mediated injury affecting the skin, vasculature, cartilage, and internal organs. The external ear, owing to its unique composition of elastic cartilage, thin dermis, and end-arterial vasculature, represents a visible and diagnostically informative site of connective tissue disease involvement. Auricular lesions may manifest as erythematous chondritis, purpura, necrosis, nodules, or sclerotic plaques, often providing dermatologists with early clinical clues to systemic disease. This review focuses on the dermatologic and histopathologic features of ear involvement in connective tissue diseases, including relapsing polychondritis, systemic lupus erythematosus, rheumatoid arthritis, granulomatosis with polyangiitis, levamisole-adulterate-cocaine-associated anti-neutrophil cytoplasmic antibody vasculitis, dermatomyositis, systemic sclerosis, Cogan syndrome, and mixed connective tissue disease. Although audio-vestibular dysfunction may accompany these diseases, the emphasis here is on the cutaneous, vascular, and chondral manifestations visible to dermatologists,with correlation of the histopathology with clinical morphology. Enhanced recognition of auricular signs can facilitate earlier diagnosis, guide biopsy, and prompt appropriate multidisciplinary evaluation.